Display and Method for Modifying Color Resists of Color Filter
A method for modifying color resists of color filter includes the steps of: providing a white light-emitting diode (WLED) emitting light having wavelength of λi and having an emission spectrum BL(λi); providing a color filter comprising a plurality of red, green and blue color resists and having a transmission spectrum CF(λi); modifying compositions or concentrations of pigments of the red color resists to increase transmission rate of the wavelength λi ranging between 580 nm and 600 nm for the red color resists; and modifying compositions or concentrations of pigments of the green color resists to increase transmission rate of the wavelength λi ranging between 570 nm and 590 nm for the green color resists. A display is also disclosed herein.
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This application claims priority to Taiwan Patent Application Serial Number 97142412, filed Nov. 3, 2008, which is herein incorporated by reference.
BACKGROUND1. Field of Invention
The present invention relates to a display and method for modifying color resists of a color filter therein. More particularly, the present invention relates to a display having a WLED backlight module and method for modifying color resists of a color filter therein.
2. Description of Related Art
Light-emitting diodes are gradually employed as a backlight source in backlight modules of liquid crystal displays due to their advantages such as power-saving, small volume, etc. However, for a liquid crystal display using white light-emitting diodes (WLEDs) as a backlight source, the color performance is usually different from that of the display using cold cathode fluorescent lamps (CCFLs) because the WLEDs emit white light after blue LED grains react with green and red phosphors therein, such that the colors shown on the display using the WLEDs are not fully expected or natural, or even fail to meet the universal standards such as sRGB (standard RGB) or EBU (European Broadcasting Union). As a result, for the display using the WLEDs as a backlight source, the colors shown on a CIE 1931 chrominance chart may have problems such as the red, green and blue colors all having deviations.
SUMMARYIn accordance with one embodiment of the present invention, a display is provided. The display includes a white light-emitting diode (WLED) and a color filter. The WLED is provided for emitting light having wavelength of λi and has an emission spectrum BL(λi). The color filter corresponds to the WLED and comprises a plurality of red, green and blue color resists, in which the color filter has a transmission spectrum CF(λi). The emission spectrum BL(λi) and the transmission spectrum CF(λi) have specific relations therebetween, as follows:
Y(λi)=CF(λi)×BL(λi), λi=λ1;
MAX(λi)=MAX[CF(λi)×BL(λi)], λi=λ2;
0.20−≦Y(λ1)/MAX((λ2)≦1;
wherein the wavelength λi ranges between 590 nm and 600 nm, Y(λ1) is a product of the transmission spectrum CF(λ1) and the emission spectrum BL(λ1), MAX(λ2) is a maximum of the product of the transmission spectrum CF(λ2) and the emission spectrum BL(λ2).
In accordance with another embodiment of the present invention, a method for modifying color resists of color filter is provided. The method comprises the steps of: providing a white light-emitting diode (WLED) emitting light having wavelength of λi and having an emission spectrum BL(λi); providing a color filter comprising a plurality of red, green and blue color resists and having a transmission spectrum CF(λi); modifying compositions or concentrations of pigments of the red color resists to increase transmission rate of the wavelength λi ranging between 580 nm and 600 nm for the red color resists; and modifying compositions or concentrations of pigments of the green color resists to increase transmission rate of the wavelength λi ranging between 570 nm and 590 nm for the green color resists.
In accordance with yet another embodiment of the present invention, a display is provided. The display includes a white light-emitting diode (WLED) and a color filter. The WLED emits light having wavelength of λi and has an emission spectrum BL(λi). The color filter corresponds to the WLED and comprises a plurality of red, green and blue color resists. The red color resists have pigments with compositions or concentrations capable of increasing transmission rate of the wavelength λi ranging between 580 nm and 600 nm for the red color resists, and the green color resists have pigments with compositions or concentrations capable of increasing transmission rate of the wavelength λi ranging between 570 nm and 590 nm for the green color resists.
It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the invention as claimed.
The invention can be more fully understood by reading the following detailed description of the embodiments, with reference to the accompanying drawings as follows:
In the following detailed description, the embodiments of the present invention have been shown and described. As will be realized, the invention is capable of modification in various respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not restrictive.
The WLEDs in the backlight module 102 are provided for emitting light having wavelength of λi and have an emission spectrum BL(λi), and the color filter has a transmission spectrum CF(λi). In one embodiment, the compositions or concentrations of pigments of the red, green and blue color resists 114 on the color filter 104 can be modified such that the emission spectrum BL(λi) and the transmission spectrum CF(λi) have specific relations therebetween, as follows:
Y(λi)=CF(λi)×BL(λi), λi=λ1;
MAX(λi)=MAX[CF(λi)×BL(λi)], λi=λ2;
0.20≦Y(λ1)/MAX(λ2)≦1;
in which the wavelength λ1 can range between 590 nanometer (nm) and 600 nm, the wavelength λ2 can be the wavelength of red, green or blue light, Y(λ1) is defined as a product of the transmission spectrum CF(λ1) and the emission spectrum BL(λ1), MAX(λ2) is defined as a maximum of the product of the transmission spectrum CF(λ2) and the emission spectrum BL(λ2).
The following are several embodiments specifically describing the specific relations between the emission spectrum BL(λi) and the transmission spectrum CF(λi) according to different wavelengths and the conditions after they are transmitted through the color filter 104.
First EmbodimentIn the present embodiment, the emission spectrum BL(λi) of the WLEDs has a relatively maximum brightness peak when the wavelength λi ranges between 430 nm and 470 nm, 490 nm and 570 nm, and 600 nm and 680 nm, respectively. The wavelength λ1 can be approximately 595 nm, and the wavelength λ2 can range between 620 nm and 680 nm (within band of red light). At that moment, the emission spectrum BL(λi) and the transmission spectrum CF(λi) have specific relations therebetween, as follows:
Y(λ1)=CF(λ1)×BL(λ1);
MAX(λ2)=MAX[CF(λ2)×BL(λ2)];
0.55≦Y(λ1)/MAX(λ2)≦1;
that is, when the wavelength λ1 is 595 nm and the wavelength λ2 ranges between 620 nm and 680 nm (within band of red light), the ratio of the product Y(λ1), i.e. Y(595), of the transmission spectrum CF(λ1) and the emission spectrum BL(λ1) to the maximum MAX(λ2) of the product of the transmission spectrum CF(λ2) and the emission spectrum BL(λ2) ranges from 0.55 to 1. In another embodiment, for the same conditions described above, the ratio of Y(λ1) to MAX(λ2) can even range from 0.65 to 1.
As shown in
Furthermore, for convenient analysis,
In the present embodiment, the emission spectrum BL(λi) of the WLEDs has a relatively maximum brightness peak when the wavelength λi ranges between 430 nm and 470 nm, 490 nm and 570 nm, and 600 nm and 680 nm, respectively. The wavelength λ1 can be approximately 595 nm, and the wavelength λ2 can range between 490 nm and 570 nm (within band of green light). At that moment, the emission spectrum BL(λi) and the transmission spectrum CF(λi) have specific relations therebetween, as follows:
Y(λ1)=CF(λ1)×BL(λ1);
MAX(λ2)=MAX[CF(λ2)×BL(λ2)];
0.55≦Y(λ1)/MAX(λ2)≦1;
that is, when the wavelength λ1 is 595 nm and the wavelength λ2 ranges between 490 nm and 570 nm (within band of green light), the ratio of the product Y(λ1), i.e. Y(595), of the transmission spectrum CF(λ1) and the emission spectrum BL(λ1) to the maximum MAX(λ2) of the product of the transmission spectrum CF(λ2) and the emission spectrum BL(λ2) ranges from 0.55 to 1. In another embodiment, for the same conditions described above, the ratio of Y(λ1) to MAX(λ2) can even range from 0.7 to 1.
As shown in
In the present embodiment, the white balance color temperature of the display ranges between 5000 K and 8500 K. The emission spectrum BL(λi) of the WLEDs has a relatively maximum brightness peak when the wavelength λi ranges between 430 nm and 470 nm, 490 nm and 570 nm, and 600 nm and 680 nm, respectively. The wavelength λ1 can be approximately 595 nm, and the wavelength λ2 can range between 430 nm and 470 nm (within band of blue light). At that moment, the emission spectrum BL(λi) and the transmission spectrum CF(λi) have specific relations therebetween, as follows:
Y(λi)=CF(λ1)×BL(λ1);
MAX(λ2)=MAX[CF(λ2)×BL(λ2)];
0.25≦Y(λ1)/MAX(λ2)≦1;
that is, when the wavelength λ1 is 595 nm and the wavelength λ2 ranges between 430 nm and 470 nm (within band of blue light), the ratio of the product Y(λ1), i.e. Y(595), of the transmission spectrum CF(λ1) and the emission spectrum BL(λ1) to the maximum MAX(λ2) of the product of the transmission spectrum CF(λ2) and the emission spectrum BL(λ2) ranges from 0.25 to 1. In another embodiment, for the same conditions described above, the ratio of Y(λ1) to MAX(λ2) can even range from 0.3 to 1.
As shown in
In the present embodiment, the white balance color temperature of the display ranges between 8500 K and 11500 K. The emission spectrum BL(λi) of the WLEDs has a relatively maximum brightness peak when the wavelength λi ranges between 430 nm and 470 nm, 490 nm and 570 nm, and 600 nm and 680 nm, respectively. The wavelength λ1 can be approximately 595 nm, and the wavelength λ2 can range between 430 nm and 470 nm (within band of blue light). At that moment, the emission spectrum BL(λi) and the transmission spectrum CF(λi) have specific relations therebetween, as follows:
Y(λ1)=CF(λ1)×BL(λ1);
MAX(λ2)=MAX[CF(λ2)×BL(λ2)];
0.2≦Y(λ1)/MAX(λ2)≦1;
that is, when the wavelength λ1 is 595 nm and the wavelength λ2 ranges between 430 nm and 470 nm (within band of blue light), the ratio of the product Y(λ1), i.e. Y(595), of the transmission spectrum CF(λ1) and the emission spectrum BL(λ1) to the maximum MAX(λ2) of the product of the transmission spectrum CF(λ2) and the emission spectrum BL(λ2) ranges from 0.2 to 1.
When the compositions or concentrations of the pigments of the red, green and blue color resists 114 on the color filter 104 are modified such that the emission spectrum BL(λi) of the WLEDs and the transmission spectrum CF(λi) of the color filter 104 meet one of the foregoing specific relations, the red image shown on the display 100 has an X-axis chrominance value ranging from 0.635 to 0.75 (0.635≦Rx≦0.75) on the CIE 1931 chrominance chart; the green image shown on the display 100 has an Y-axis chrominance value ranging from 0.595 to 0.85 (0.595≦Gy≦0.85) on the CIE 1931 chrominance chart; the blue image shown on the display 100 has an Y-axis chrominance value ranging from 0 to 0.065 (0≦By≦0.065) on the CIE 1931 chrominance chart. As a result, the image shown on the display 100 can thus meet the chrominance standard of sRGB. In one embodiment, the chrominance coordinates (Rx, Ry) of the red color is (0.64, 0.33), the chrominance coordinates (Gx, Gy) of the green color is (0.30, 0.60), and the chrominance coordinates (Bx, By) of the blue color is (0.15, 0.06).
Moreover, even if different WLEDs are provided as a backlight source, the color resists 114 on the color filter 104 can also be modified such that the emission spectrum BL(λi) of a new backlight source and the transmission spectrum CF(λi) of the color filter 104 meet one of the foregoing specific relations as well, and the image shown on the display 100 can thus meet the chrominance standard of sRGB.
On the other hand, the relations of the transmission spectrum CF(λi) and the emission spectrum BL(λi) described above can also be employed in the larger size display (e.g. flat TV) such that the image shown on the display can meet the chrominance standard of EBU (European Broadcasting Union) when the emission spectrum BL(λi) and the transmission spectrum CF(λi) have one of the foregoing specific relations therebetween. EBU is the chrominance standard adopted by the conventional European TVs, and its chrominance coordinates (Rx, Ry) of the red color is (0.64, 0.33), its chrominance coordinates (Gx, Gy) of the green color is (0.29, 0.60), and its chrominance coordinates (Bx, By) of the blue color is (0.15, 0.06); sRGB is the chrominance standard adopted by the conventional IT products. The difference between EBU and sRGB is that the X-axis chrominance values Gx of the green color of both are different; however, the methods described in the foregoing embodiments of the present invention would not affect the chrominance value Gx of the green color. Therefore, the methods described in the foregoing embodiments of the present invention can be employed both in the display with the chrominance standard of sRGB and in the display with the chrominance standard of EBU.
In addition, a method for modifying the color resists of the color filter is also provided according to one embodiment of the present invention, so as to improve the image shown on the display.
After that, the compositions or concentrations of the pigments of the red color resists are modified to increase the transmission rate of the wavelength λi ranging between 580 nm and 600 nm for the red color resists (Step 504), and the compositions or concentrations of the pigments of the green color resists are modified to increase the transmission rate of the wavelength λi ranging between 570 nm and 590 nm for the green color resists (Step 506). Afterwards, the compositions or concentrations of the pigments of the blue color resists are modified to increase the color saturation of the blue color resists (Step 508). In one embodiment, the compositions or concentrations of the pigments of the red color resists are modified such that the transmission rate of the wavelength λi being approximately 590 nm for the red color resists is increased, and the compositions or concentrations of the pigments of the green color resists are modified such that the transmission rate of the wavelength λi being approximately 580 nm for the green color resists is increased.
Notably, Steps 500 and 502 can be alternately performed or even performed at the same time, and Steps 504, 506 and 508 for modifying the color resists also can be alternately performed or even performed at the same time, and not limited to what is shown in
Then, if the emission spectrum BL(λi) and the transmission spectrum CF(λi) having specific relations therebetween according to the modified red color resists and green color resists, as follows, is determined (Step 510).
Y(λi)=CF(λi)×BL(λi), λi=λ1;
MAX(λi)=MAX[CF(λi)×BL(λi)], λi=λ2;
0.55≦Y(λ1)/MAX(λ2)≦1;
in which the wavelength λ1 can be approximately 595 nm, the wavelength λ2 ranges between 620 nm and 680 nm, Y(λ1) is a product of the transmission spectrum CF(λ1) and the emission spectrum BL(λ1), MAX(λ2) is a maximum of the product of the transmission spectrum CF(λ2) and the emission spectrum BL(λ2).
If the emission spectrum BL(λi) and the transmission spectrum CF(λi) have the specific relations described above, therebetween, modifying the compositions or concentrations of the pigments of the red and green color resists will not be necessary. On contrary, if the emission spectrum BL(λi) and the transmission spectrum CF(λi) fail to have the specific relations described above, therebetween, the compositions or concentrations of the pigments of the red and green color resists are re-modified (Step 512). After that, Step 510 is performed again to determine if the emission spectrum BL(λi) and the transmission spectrum CF(λi) have the specific relations therebetween.
For the foregoing embodiments, the display and the method for modifying the color resists of the color filter described above can be employed to improve the color performance of the displayed image such that the color performance can be more natural and the chrominance of the displayed image can meet the standard of sRGB or EBU when the display utilizes WLEDs as a backlight source.
As is understood by a person skilled in the art, the foregoing embodiments of the present invention are illustrative of the present invention rather than limiting of the present invention. It is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structures.
Claims
1. A display, comprising:
- a white light-emitting diode (WLED), for emitting light having wavelength of λi, having an emission spectrum BL(λi); and
- a color filter corresponding to the WLED and comprising a plurality of red, green and blue color resists, the color filter having a transmission spectrum CF(λi);
- wherein the emission spectrum BL(λi) and the transmission spectrum CF(λi) have specific relations therebetween, as follows: Y(λi)=CF(λi)×BL(λi), λi=λ1; MAX(λi)=MAX[CF(λi)×BL(λi)], λi=λ2; 0.20≦Y(λi)/MAX(λ2)≦1;
- wherein the wavelength λ1 ranges between 590 nm and 600 nm, Y(λ1) is a product of the transmission spectrum CF(λ1) and the emission spectrum BL(λ1), MAX(λ2) is a maximum of the product of the transmission spectrum CF(λ2) and the emission spectrum BL(λ2).
2. The display as claimed in claim 1, wherein the wavelength λ1 is approximately 595 nm.
3. The display as claimed in claim 2, wherein Y(λ1) and MAX(λ2) further have another specific relation therebetween, as follows: and the wavelength λ2 ranges between 620 nm and 680 nm.
- 0.55≦=Y(λ1)/MAX(λ2)≦1,
4. The display as claimed in claim 2, wherein a white balance color temperature of the display ranges between 8500 K and 11500 K.
5. The display as claimed in claim 4, wherein the wavelength λ2 ranges between 430 nm and 470 nm.
6. The display as claimed in claim 2, wherein a white balance color temperature of the display ranges between 5000 K and 8500 K.
7. The display as claimed in claim 6, wherein Y(λ1) and MAX(λ2) further have another specific relation therebetween, as follows: and the wavelength λ2 ranges between 430 nm and 470 nm.
- 0.25≦Y(λ1)/MAX(λ2)≦1,
8. The display as claimed in claim 1, wherein Y(λ1) and MAX(λ2) further have another specific relation therebetween, as follows: and the wavelength λ2 ranges between 620 nm and 680 nm.
- 0.65≦Y(λ1)/MAX(λ2)≦1,
9. The display as claimed in claim 1, wherein Y(λ1) and MAX(λ2) further have another specific relation therebetween, as follows: and the wavelength λ2 ranges between 490 nm and 570 nm.
- 0.70≦Y(λ1)/MAX(λ2)≦1,
10. The display as claimed in claim 1, wherein Y(λ1) and MAX(λ2) further have another specific relation therebetween, as follows: and the wavelength λ2 ranges between 430 nm and 470 nm.
- 0.25≦Y(λi)/MAX(λ2)≦1,
11. The display as claimed in claim 1, wherein a red image shown on the display has an X-axis chrominance value ranging from 0.635 to 0.75 on a CIE 1931 chrominance chart.
12. The display as claimed in claim 1, wherein a green image shown on the display has a Y-axis chrominance value ranging from 0.595 to 0.85 on a CIE 1931 chrominance chart.
13. The display as claimed in claim 1, wherein a blue image shown on the display has a Y-axis chrominance value ranging from 0 to 0.065 on a CIE 1931 chrominance chart.
14. A method for modifying color resists of color filter, comprising:
- providing a white light-emitting diode (WLED) emitting light having wavelength of λi and having an emission spectrum BL(λi);
- providing a color filter comprising a plurality of red, green and blue color resists and having a transmission spectrum CF(λi);
- modifying compositions or concentrations of pigments of the red color resists to increase transmission rate of the wavelength λi ranging between 580 nm and 600 nm for the red color resists; and
- modifying compositions or concentrations of pigments of the green color resists to increase transmission rate of the wavelength λi ranging between 570 nm and 590 nm for the green color resists.
15. The method as claimed in claim 14, further comprising:
- determining if the emission spectrum BL(λi) and the transmission spectrum CF(λi) having specific relations therebetween according to the modified red color resists and green color resists, as follows: Y(λi)=CF(λi)×BL(λi), λi=λ1; MAX(λi)=MAX[CF(λi)×BL(λi)], λi=λ2; 0.55≦Y(λ1)/MAX(λ2)≦1;
- wherein the wavelength λ1 is approximately 595 nm, the wavelength λ2 ranges between 620 nm and 680 nm, Y(λ1) is a product of the transmission spectrum CF(λ1) and the emission spectrum BL(λ1), MAX(λ2) is a maximum of the product of the transmission spectrum CF(λ2) and the emission spectrum BL(λ2).
16. The method as claimed in claim 15, further comprising:
- re-modifying the compositions or concentrations of the pigments of the red and green color resists when the emission spectrum BL(λi) and the transmission spectrum CF(λi) failing to have the specific relations therebetween.
17. The method as claimed in claim 14, further comprising:
- modifying compositions or concentrations of pigments of the blue color resists to increase color saturation of the blue color resists.
18. The method as claimed in claim 14, wherein the compositions or concentrations of the pigments of the red color resists are modified such that the transmission rate of the wavelength λi being approximately 590 nm for the red color resists is increased, and the compositions or concentrations of the pigments of the green color resists are modified such that the transmission rate of the wavelength λi being approximately 580 nm for the green color resists is increased.
19. A display, comprising:
- a white light-emitting diode (WLED) as claimed in claim 14; and
- a color filter corresponding to the WLED and comprising a plurality of red, green and blue color resists;
- wherein the red color resists have the pigments with the modified compositions or concentrations as claimed in claim 15, and the green color resists have the pigments with the modified compositions or concentrations as claimed in claim 15.
20. The display as claimed in claim 19, wherein the blue color resists have the pigments with the modified compositions or concentrations as claimed in claim 17.
Type: Application
Filed: Feb 23, 2009
Publication Date: May 6, 2010
Patent Grant number: 8102602
Applicant: AU OPTRONICS CORPORATION (Hsin-Chu)
Inventors: Ya-Ling Hsu (Hsin-Chu), Chun-Liang Lin (Hsin-Chu), Chun-Chieh Wang (Hsin-Chu), Chen-Hsien Liao (Hsin-Chu)
Application Number: 12/390,627
International Classification: F21V 9/00 (20060101); G02F 1/355 (20060101);